title: Evidence that Xenopus laevis contains two different nonallelic insulin-like growth factor-I genes.
abstract: Using the polymerase chain reaction (PCR), we have amplified and characterized partial nucleotide sequences of two distinct insulin-like growth factor-I genes (designated IGF-I' and IGF-I") from the amphibian, Xenopus laevis. The amplified fragments encoded much of the coding region of the mature peptide (exon III in mammalian IGF-I genes), and exhibited 93% similarity to each other, and 68-82% similarity to mammalian IGF-I amino acid sequences. Southern blot analysis using genomic DNA from a homozygous frog revealed that these two genes are nonallelic in a single organism, like the two nonallelic genes encoding Xenopus insulins that we have characterized previously. Furthermore, both IGF-I mRNAs are expressed in similar quantities in adult liver.
authors.affiliation: Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: A R
authors.initials: AR
authors.lastname: Shuldiner
authors.forename: A
authors.initials: A
authors.lastname: Nirula
authors.forename: L A
authors.initials: LA
authors.lastname: Scott
authors.forename: J
authors.initials: J
authors.lastname: Roth
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D004247:DNA / Q000235:genetics; D005796:Genes; D006720:Homozygote; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008099:Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D015345:Oligonucleotide Probes / Q000138:chemical synthesis; D016133:Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D013002:Somatomedins / Q000235:genetics*; D014982:Xenopus laevis / Q000235:genetics*
chemical_list: D015345:Oligonucleotide Probes; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D004247:DNA